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| author | priyanka | 2015-06-24 15:03:17 +0530 |
|---|---|---|
| committer | priyanka | 2015-06-24 15:03:17 +0530 |
| commit | b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b (patch) | |
| tree | ab291cffc65280e58ac82470ba63fbcca7805165 /581/CH7/EX7.6/Example7_6.sce | |
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Diffstat (limited to '581/CH7/EX7.6/Example7_6.sce')
| -rwxr-xr-x | 581/CH7/EX7.6/Example7_6.sce | 32 |
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diff --git a/581/CH7/EX7.6/Example7_6.sce b/581/CH7/EX7.6/Example7_6.sce new file mode 100755 index 000000000..c417325b0 --- /dev/null +++ b/581/CH7/EX7.6/Example7_6.sce @@ -0,0 +1,32 @@ +
+clear;
+clc;
+
+printf("\t Example 7.6\n");
+
+Tbin=290; //inlet bulk temp.,K
+v=1; //speed of air, m/s
+a=0.09; //area of steel,m^2
+l=15; //length of duct running outdoors through awarm air,m
+To=310; //temp. of warm air,K
+h=5; //heat transfer coefficient due to natural convection and thermal radiation.
+Dh=0.3; //hydraulic diameter,m
+Re=v*Dh/(1.578*10^-5); //reynolds no.at Tbin
+Pr=0.713; //prandtl no.
+
+f=1/(1.82/2.303*log(Re)-1.64)^2; // formula for friction factor for smooth pipes
+
+Nu=(f/8*Re*Pr)/(1.07+12.7*(f/8)^(0.5)*(Pr^(2/3)-1)); //formula for nusselt no.in fully developed flow in smooth pipes
+
+
+h=Nu*0.02623/Dh; // convective heat transfer coefficient,W/(m^2)/K
+//the remaining problem is to find the bulk temperature change.the thin metal duct wall offers little thermal ressistance, but convection ressistance outside the duct must be considered.
+
+U=(1/4.371+1/5)^-1; //U=1/Ain*(1/(h*A)in+1/(h*A)out)^-1
+
+
+Tbout=(To-Tbin)*(1-exp(-U*4*l/(1.217*v*1007*Dh)))+Tbin; //outlet bulk temp., K
+Tbt1=Tbout-273;
+
+printf("\t outside bulk temp. change is : %.1f C\n",Tbt1);
+//end
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